Publications by authors named "Eduardo G Vieira"

In this work, a polyhedral silsesquioxane (POSS) was used as an engineered drug delivery system for two oxindolimine-copper(II) anticancer complexes, [Cu(isaepy)] and [Cu(isapn)]. The interest in hybrid POSS comes from the necessity of developing materials that can act as adjuvants to improve the cytotoxicity of non-soluble metallodrugs. Functionalization of POSS with a triazole ligand (POSS-atzac) permitted the anchorage of such copper complexes, producing hybrid materials with efficient cytotoxic effects.

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A novel strategy of improving cytotoxicity against metastatic melanoma cells using an oxindolimine copper(ii) complex immobilized and dimerized on a modified Polyhedral Oligomeric Silsesquioxane (POSS) matrix was developed, as revealed by electron paramagnetic resonance (EPR) spectroscopy. An assured correlation between continuous-wave (CW) and pulsed EPR spectroscopies provided a complete characterization of the actual active species, its coordination environment, as well as the efficiency/selectivity of the bioconjugate materials.

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Studies on the immobilization of oxindolimine‑copper(II) or zinc(II) complexes [ML] in synthetic beidellite (BDL) clay were developed to obtain a suitable inorganic carrier capable of promoting the modified-release of metallopharmaceuticals. Previous investigations have shown that the studied metal complexes are promising antitumor agents, targeting DNA, mitochondria, and some proteins. They can bind to DNA, causing oxidative damage via formation of reactive oxygen species (ROS).

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Currently the only drug available to treat Chagas disease in Brazil is benznidazole (BZN). Therefore, there is an urgent need to discover and develop new anti- Trypanosoma cruzi candidates. In our continuous effort to enhance clinical antiparasitic drugs using synergistic strategy, BZN was coordinated to silver and copper ions to enhance its effectiveness to treat that illness.

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Article Synopsis
  • A series of transition metal coordination polymers containing zinc and copper were synthesized using fluconazole and various metal salts under mild conditions, resulting in six new compounds.
  • The structures of these compounds were confirmed through various analytical techniques, including single-crystal X-ray diffraction for four of the compounds.
  • The compounds showed significant antichagasic activity against Trypanosoma cruzi, with one compound (2) being particularly effective, suggesting that these coordination polymers could be better therapeutic options than the free azole drug for Chagas disease.
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A new rutin copper(II) complex (R-Cu2) was prepared and characterized by spectroscopic methods and elemental analysis. The effects of rutin and R-Cu2 were evaluated on the prevention of hypercholesterolemia in animals feed with high-cholesterol diet (HCD) for 8 weeks. The animals (n = 5) were neither fed with HCD nor treated (control group), or were treated with vehicle, 10 mg/kg simvastatin, rutin (16 and 160 μmol/kg), and R-Cu2 (16 and 160 μmol/kg) administered orally.

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A series of new metal complexes, [Zn(KTZ)(Ac)]·HO (1) [Zn(KTZ)Cl]·0.4CHOH (2), [Zn(KTZ)(HO)(NO)](NO) (3), [Cu(KTZ)(Ac)]·HO (4) [Cu(KTZ)Cl]·3.2HO (5), [Cu(KTZ)(HO)(NO)](NO)·HO (6), were synthesized by a reaction of ketoconazole (KTZ) with their respective zinc or copper salts under mild conditions.

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In this review we compare and discuss results of compounds already reported as anticancer agents based on isatin-derivatives, metalated as well as non-metallated. Isatin compounds can be obtained from plants, marine animals, and is also found in human fluids as a metabolite of amino acids. Its derivatives include imines, hydrazones, thiosemicarbazones, among others, already focused on numerous anticancer studies.

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In this work, a silica surface chemically modified with [3-(2,2'-dipyridylamine)propyl] groups, named [3-(2,2'-dipyridylamine)propyl]silica (Si-Pr-DPA) was prepared, characterized, and evaluated for its heavy metal adsorption characteristics from aqueous solution. To our knowledge, we are the first authors who have reported the present modification. The material was characterized using infrared spectroscopy, SEM, and NMR (29) Si and (13) C solid state.

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A silica surface chemically modified with [3-(2,2'-dipyridylamine) propyl] groups was prepared, characterized, and evaluated for its metal ion preconcentration in fuel ethanol. To our knowledge, we are the first authors who have reported the present modification on silica gel surface. The material was characterized using infrared spectra, scanning electronic microscopy, and (13)C and (29)Si solid-state NMR spectra.

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In this work, a new modified oligosilsesquioxane was prepared, characterized and evaluated for its heavy metal adsorption characteristics from aqueous solution. The material was characterized using infrared spectroscopy, X-ray diffractometry, solid-state (29)Si and (13)C nuclear magnetic resonance. Batch and column experiments were conducted to investigate for Fe (III), Cr (III), Cu (II), Cd (II), Pb (II) and Ni (II) removal from dilute aqueous solution by sorption onto modified oligosilsesquioxane.

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